Piston for internal combustion engines



2 Sheets-Shee-t 1\ Aug. 9, 1938. A. L. R. BERNARD PISTON FOR NTERNAL CONIBUSTION ENGINES Filed Dem 1'?,` 1934 Aug. 9, 1938. A.`L, R. BERNARDv 2,125,306

PIsToN Foa INTERNAL coNusTIoN ENGINES Filed Dec. 17. 1954 2 sheets-sheet 2 Patented Aug. 9, 1938 UNITED vSTATES PATENT GFFICEl PISTON FOR INTERNAL COMBUSTION ENGINES Auguste Louis Ren Bernard, deceased, late of Rueil-Malmaison, France, by Rene Bernard, ne Bournonville, executrix, Paris, France Application December 17, 1934, Serial No. 757,977 In Belgium December 22, 1933 13 Claims.

a piston which is better adapted to meet the requirements oi actual practice.

The essential featureof the present invention E() consists in providing a piston with means, located under the piston head and extending between the central portion of said piston head and the piston skirt, for shoring up said piston head.

Another feature of the invention consists in 115 providing an annular cushion of a compressible material, such for instance as a compressed metallic powder, under the peripheral portion of the piston head and upon the upper portion of the `skirt of said piston.

Other features of the present invention will result from the following detailed description of some specific embodiments thereof. Preferred embodiments of the present invention will be hereinafter described, with reference g5 to the accompanying drawings, given merely by way of example, and in which:

Fig. 1 is an axial section view of a piston according to the present invention;

Fig. 2 is an axial section view of another em- '30 bodiment of the piston according to the present invention, also showing the walls of the cylinder `in which said piston `is tted and the combustion chamber;

Fig. 3 lis a sectional view of another embodi- 35 ment of the piston;

Fig. 4 is a View similar to Fig. 2, showing still another embodiment of the piston according to the present invention.

According to the present invention, and as 40 shown by the drawings, relating to several embodiments of the invention, there is provided, below piston head I and between the central portion of said piston head and the peripheral walls, or skirt, of said piston, means for shoring up said piston.`

` Preferably, these means are so devised as to support the piston head along an annular zone thereof, and these means are themselves supported, along the circumference of the piston skirt, by an annular projection 2 carried by said piston skirt, either below the zone carrying the packing rings, as in the embodiments of Figs. 2 and 4, or at least below the upper packing rings, as in the embodiments of Figs. 1 and 3. y z For this purpose, in the embodiments of Figs.

1 and 4, the inner face of piston head l is provided with a tubular part 3 extending inwardly, and preferably coaxially, in said piston.. This tubular part 3 bears against a kind of partition 4 itself supported by annular part 2 of the piston skirt, either directly, as shown by Figs. 1 and 4, or indirectly, as shown by Fig. 2. Advantageously, partition 4 is cup-shaped and its convexity is turned toward the piston head I.

Of course, the arrangement above described is applicable as well in the case in which the piston head is made of several parts, consisting of different metals, as shown by Fig. l, as in the case in which said piston head is made of a single part, r l

In the embodiment of Fig. 2, piece 5 is made of a light weight metal for instance, and its lower bearing portion or shoulder 5 is interposed between the partition 4 and the annular part 2, While in the embodiment of Fig. 3 piece 5 is advantageously made of steel.

It will be readily understood that, with either of the embodiments above described, the arrangement according to the present invention makes it possible to considerably reduce the weight of the piston head since it prevents sagging thereof under the effect of the high pressures that are applied thereon.

This advantage is particularly important in the case of internal combustion engines in which the piston head is provided with a substantially conical projection 6 (Figs. 2 and 4) adapted for instance to penetrate into a tore-shaped compression chamber l and upon the top` of which is directed and impinges the jet from injector 8.

As a rule, in this case, the piston head has the approximate shape of a cone having concave generatrices and which therefore is not well adapted to resist crushing stresses.

Furthermore, piston heads of this kind must be made of a material, such as a special steel, which is capable of withstanding very high temperatures, and, as a rule, such a material has very bad mechanical properties, especially at the temperatures at which it is caused to work. However, owing to the provision of the means for roV shoring up the central part of the piston head as above described, it is not necessary to have piston heads of very great thickness.

Furthermore these means for shoring up the central part of the piston head constitute a supplementary way for the outflow of the heat transmitted to the piston head.

Of course, said means may be established either in a continuous form, for instance by making use of a tubular partition, so as to provide between said means and the peripheral part of the piston head a closed chamber 9, or in a` discontinuous form if said chamber 9 communicates with the inside of the piston through apertures.

The arrangement above described may also include the following feature, which further increases the advantages above referred to.

According to this feature, there is provided an annular cushion of a compressible material which is a good conductor of heat, such as slightly cornpressed metallic powder, runder the peripheral portion of the piston head and against the upper portion of the piston skirt.

If the piston is made as above described, this cushion shall advantageously be placed in chamber 9, which will then be tightly closed, as shown 'in the embodiments of Figs. l, 2 and 4.

This cushion, which may for instance consist of aluminium powder suiciently compressed in order that its density may range between 1.6 and 1.8, will further insure, besides fluid tightness of the joints in the piston, a good thermic contact of the various elements of said piston, whether their coeicients of dilatation are substantially equal or not, and finally a better flow of the heat toward the portions of the piston skirt located below the zone carrying packing rings I0, and especially the upper packing rings.

In the particular case of pistons provided with the conical projection 6 above referred to, the annular cushion of metallic powder has the further advantage of making it possible to keep the central portion of the piston head (therefore projection E) at a temperature suilciently high for ensuring a good working of the engine. As a matter of fact, this temperature must generally be substantially higher than the temperature of the peripheral portion of the piston head.

The latter shall ltherefore be cooled in the -best possible manner and the packing rings will be protected in a satisfactory manner against the action of heat, in spite -of the high temperature of the central zone of the piston.

Although the characteristic features that have been described may be carried out in many ways, and independently of one another, l'. have found that it is advantageous to combine them as shown in `the embodiment of Figs. .2 and 4, as it will be hereinafter explained.

A tubular element adapted to play the part of a piston skirt and provided with packing rings IU, is made of any suitable metal, such for instance as cast iron.

In the lower part of this piston skirt is inserted a kind of sleeve I2, advantageously made of two symmetrical parts, each carrying a projection |31, I32 respectively, said projections being engaged in a tube I4, which constitutes the gudgeon pin of the piston.

On the inner wall of skirt is provided an annular shoulder I5 against which is applied the upper edge of sleeve I2 when the latter is held inv position as shown in Fig. 4 by an annular nut I6 which is screwed into skirt from the bottom thereof, or by screw threads I6Y on the outer Wall of sleeve |2 cooperating with similar threads at the inner wall of skirt I, as shown by Fig. 2.

The head I of the piston is made of special steel and its central part is provided with the projection 6 above referred to. .On the inner side, said central part of the piston head is further provided with tubular part 3.

Means are provided for assembling by screwing the piston head with the piston skirt I I, said means consisting for instance of an annular nut II, according to Fig. 4, or of cooperating screw threads I'I, according to Figs. 2 and 3.

A frusto-conical piece, for instance of steel, constitutes the partition 4 above mentioned. This piece is provided at its lower end with a cylindrical edge or flange I8, of bevel-shaped section, adapted to be inserted with a force fit in said skirt I|, above shoulder I5. At the other end, said part 4 is provided, around the central hole with which it is provided, with another cylindrical edge I9, analogous to the above mentioned one, and adapted to t with a force t around the tubular part 3 above referred to.

After piston head I has been fixed in position on piston skirt I I, a suicient amount of aluminium powder is poured (after having placed the piston upside down) into the annular space existing between part 3 and the top of the piston skirt, and partition 4 is forced into the position shown in the drawings, thus compressing and enclosing in chamber 9 said metallic powder.

If the various elements of the piston to be made have been suitably devised, and especially, if the amount of metal'powder is exactly measured and compressed, the lower edge of partition 4 is nally exactly flush with the edge of shoulder I5 as shown by Fig. 4, or with the upper edge of bearing portion or shoulder 5', according to Fig. 2.

If desirable, special means may be provided for keeping said partition in position, on the one hand with respect to piston head I and on the other hand with respect to the piston skirt For instance, according to Fig. 4, an annular nut 20 is rst screwed in the central hole of ele-- ment 4, said annular nut being adapted to butt against the lower edge of part 3, whereby, after assembling of the parts, the piston head is suitably supported by element 4.

On the other hand, a second nut 2| is subsequently screwed inside part 3 in such manner that, after tightening, the head of this annular nut is applied, eventually with the interposition of a suitable packing member, against the head of the above mentioned nut 20, which completes the fixation in both directions of part 3 and element 4.

Finally the sleeve I2 that has been above described is inserted in position, and the assembling of the parts is completed by screwing nut I6, the upper edge of sleeve I2 being'applied against shoulder |5 and, according to Fig. 4, also against the lower edge of element 4, so as to constitute the annular projection 2 mentioned at the beginning of this description.

While I have, in the preceding description, dis closed what I deem to be practicaland eiiicient embodiments of the present invention, it should be Well understood that I do not wish to be limited Vthereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

y1. A-piston-forfanr internal combustion engine CII mounted with a force t around said tubular part rigid with said piston head, and means carried by the last mentioned cylindrical part for bearing against the edge of said tubular part.

2. A piston according to claim 1 in which the last mentioned means consist of an outwardly threaded annular nut screwed in the last mentioned cylindrical part and adapted to butt against the edge of said tubular part.

3. A piston according to claim 1 in which the last mentioned means consist of an outwardly threaded annular nut screwed in the last mentioned cylindrical part and adapted to butt against the edge of said tubular part, further including an outwardly threaded annular nut screwed in said tubular part carried by said piston head, and a flange carried by the last mentioned nut adapted to bear upon the annular edge of the rst mentioned nut.

4. A piston according to claim l further including a compressed metal powder lling the closed space limited by said frusto-conical piece, the peripheral portion of said piston head, and the upper part of said piston skirt.

5. In an internal combustion engine, a piston comprising in combination a piston head having an upward projection at the center thereof, a

piston skirt secured to said piston head, and an annular body of compressed heat-conducting metallic powder arranged below and in contact only with that portion of the piston head adjacent the base of said projection.

6. In an internal combustion engine, a piston comprising in combination a piston head having an upward hollow conical p-rojection in the center thereof, a piston skirt secured to said piston head and an annular body of compressed heatconducting metallic powder arranged below and in contact only with that portion of the piston head adjacent the base of said projection.

7. A piston for an internal combustion injector engine comprising in combination a piston head having an upward projection at the center thereof adapted to receive a fuel jet which is directed to impinge upon the top of said projection, a piston skirt secured to said piston head, an annular body of compressed heat-conducting metallic powder arranged below and in contact only with that portion of the piston head adjacent the base of said projection.

8. In an internal combustion engine, a piston comprising in combination a piston head havingA an upward projection at the center thereof, a piston skirt secured to said piston `head adjacent the base of said projection, a tubular part secured to said projection adjacent the base thereof and extending downwardly therefrom toward the inside of said piston head, and an annular body of compressed heat-conducting metallic powder surrounding said part.

9. In an internal combustion engine, a piston comprising in combination a piston head having an upward hollow conical projection in the center thereof, a piston skirt secured to said piston head, an annular wall secured to said projection adjacent the base thereof and extending downwardly therefrom toward the inside of said piston head and forming a chamber therein, a transverse wall closing said chamber at the lower end, and an annular body of compressed heat-conducting metallic powder within said chamber surrounding said annular wall.

10. In an internal combustion engine, a piston comprising in combination, a piston head, an upward projection at the center of said piston head, a piston skirt extending downwardly from said head, and means for shoring up said piston head comprising at least one element extending downwardly from said piston head adjacent the base of said projection and secured to said piston skirt, said element, said piston head, and said skirt forming a closed annular chamber therebetween, and compressed metallic powder within said chamber.

ll. A piston comprising a head having at its center an upward projection, a skirt extending downwardly from said head, a member extending downwardly from said head adjacent the base of said projection, and an annular body of compressed heat-conducting metallic powder surrounding said member.

12. A piston comprising a head having at its center an upwardly extending portion, and an annular body of compressed metallic powder in contact only with the portions of the piston outside the vertical projection of said upwardly extending portion.

13. A piston comprising a head having at its central portion an upward projection, and a body of compressed metallic powder arranged in contact only with portions of said piston other than said central upward projection.

RENE BERNARD, NE BOURNONVILLE, Eecutrz of Auguste Louis Ren Bernard, De-

ceased.

Cri 

